Hello,
Does your office pc always remains ON and connected to internet? what operation system do you use in that office pc?
If your office pc does not stays ON all the time, I would suggest you to get a $5/per month server from DO or AWS. I will install VPN server there, then when you need to connect, you must first log in VPN. It also comes with android app to connect to VPN.
Regards,
Samiran